The researchers say a significant roadblock in algal biofuel research surrounds the production of lipid oils, the fat molecules that store energy that can be produced for fuel: algae mainly produce the desired lipid oils when they are starved for nutrients.

Yet if they are limited in nutrients, they don’t grow well. With a robust diet algae grow well, but they produce carbohydrates instead of the desired lipids for fuel.

Genetically engineering diatoms

As reported in this week’s online edition of the Proceedings of the National Academy of Sciences (open access), Scripps graduate student Emily Trentacoste and her colleagues used a data set of genetic expression (called “transcriptomics” in laboratories) to target a specific enzyme inside a group of microscopic algae known as diatoms (Thalassiosira pseudonana).

By metabolically engineering a “knock-down” of fat-reducing enzymes called lipases, the researchers were able to increase lipids (oils) without compromising growth. The genetically altered strains they developed, the researchers say, could be produced broadly in other species.

“These results demonstrate that targeted metabolic manipulations can be used to increase accumulation of fuel-relevant molecules, with no negative effects on growth,” said Trentacoste. “We have shown that engineering this pathway is a unique and practical approach for increasing lipid yields.”

“Scientifically this is a huge achievement,” said Mark Hildebrand, a marine biology professor at Scripps and a coauthor of the study. “Five years ago people said you would never be able to get more lipids without affecting growth negatively. This paper shows that there isn’t an intrinsic barrier and gives us hope of more new things that we can try — it opens the door to a lot more work to be done.”

Faster, cheaper production

In addition to lowering the cost of biofuel production by increasing lipid content, the new method has led to advances in the speed of algal biofuel crop production due to the efficient screening process used in the new study.

“Maintaining high growth rates and high biomass accumulation is imperative for algal biofuel production on large economic scales,” the authors note in the paper.

“Increasing lipid accumulation in microalgae is a major priority to boost the economic viability of algal biofuels, but growth and biomass are also important characteristics in large-scale production systems,” Trentacoste told KurzweilAI. “The specific enzyme targeted in this study is conserved throughout eukaryotes, and could be targeted in other production strains as well, thus these methods could be applied to many algal biofuel systems.

“A U.S. provisional patent application has been filed in relation to this invention,” she said. “Interested licensees can contact Dr. Donald Kakuda (dkakuda@ucsd.edu) at University of California-San Diego’s Technology Transfer Office.”

The National Institutes of Health, California Energy Commission, Air Force Office of Scientific Research, Department of Energy, and National Science Foundation supported the research.

Abstract of Proceedings of the National Academy of Sciences paper

Biologically derived fuels are viable alternatives to traditional fossil fuels, and microalgae are a particularly promising source, but improvements are required throughout the production process to increase productivity and reduce cost. Metabolic engineering to increase yields of biofuel-relevant lipids in these organisms without compromising growth is an important aspect of advancing economic feasibility. We report that the targeted knockdown of a multifunctional lipase/phospholipase/acyltransferase increased lipid yields without affecting growth in the diatom Thalassiosira pseudonana. Antisense-expressing knockdown strains 1A6 and 1B1 exhibited wild-type–like growth and increased lipid content under both continuous light and alternating light/dark conditions. Strains 1A6 and 1B1, respectively, contained 2.4- and 3.3-fold higher lipid content than wild-type during exponential growth, and 4.1- and 3.2-fold higher lipid content than wild-type after 40 h of silicon starvation. Analyses of fatty acids, lipid classes, and membrane stability in the transgenic strains suggest a role for this enzyme in membrane lipid turnover and lipid homeostasis. These results demonstrate that targeted metabolic manipulations can be used to increase lipid accumulation in eukaryotic microalgae without compromising growth.

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comments 17

I wonder if there might be a way to economically pump the CO2 from coal plants up in the populous NorthEast (USA) to the sunny SouthWest where it would be absorbed by the algae fuel production process. The carbon might be reused in vehicles rather than ejecting it directly into the atmosphere.

You just came up with a great idea, Richard. The same pipeline that the Koch brothers are now building from Canada to Texas can have trunklines joining it to carry a slurry of that new crystalline magnesium compound down to the sunny SouthWest, then carry finished bio-diesel back up to the populous NorthEast.

Excellent , now if we combine this discovery with the recent work done by Professor Carl Johnson, we could have a biofuel production output that could make it a viable replacement for fossils.
For those unaware, the aforementioned Professor recently publish his research results on shutting down the biological clocks of microorganisms such as algae and Cyanobacteria. Read the full article here.http://bit.ly/1av4jF6

We don’t necessarily have to have the algae producing lipids, why not have them produce simple fuels like isobutanol or even hydrogen or methane directly. With the right collaboration of GE, the possibilities could be endless.

Of course, the sun doesn’t shine 24/7 to keep up with the sleepless bio factories we make but we can provide the organisms with artificial light to grow. The naysayers will be quick to point out that the lights consume the energy we are trying to make. But if we use the energy from another renewable source such as wind turbines or wave power during the night, the algae byproduct provides a great energy storage medium in whatever form we design them to make. This in turn provides us with stored energy to burn for the grid when it’s needed.

I don’t mean to be a naysayer, but engineers have an old saying, TANSTAAFL (which means, “There ain’t nosuch thing as a free lunch.” There is a loss of efficiency in making artificial light, so it wouldn’t be economical to grow algae with even the best of grow lights.

But not to worry. There is a lot of free sunlight in the Sonora Desert.

There will always be a loss of efficiency, but the trade-off is cheap energy storage in the form of liquid or gaseous fuel where the energy density is very high. Current conventional methods of storing energy from renewable sources is expensive to implement, This is one of the major roadblocks to mass implementation of renewables.

Well, of course, Ahriman, bio-diesel is the easiest of all these renewable fuels to store, transport, and use.

But it still doesn’t pay to grow it with artificial light. There is so much strong sunlight in the desert states, along with a lot of empty land, that you could grow all you want every day and let the algae rest at night.

With robots printing copies of themselves and printing all the other things to grow the algae and process it, you could have a surplus of fuel in short order.

Well, something certainly needs to be done, apparently. Seems like the commercial production of bio-fuel additives is sure falling way short of what was expected by the legislation passed to promote it.

If we (US citizens) could “grow” our own algae fuel, then perhaps we could break the political capture of the oil industry over “our” government. Perhaps one day, the broad dispersal and application of scientific knowledge could allow us to break free from other industries as well.

I heard ya, Anthony. We must break free of the chains forged by the oil industry.

Of course, if Exxon Mobil or BP of Dutch Shell were smart, they’d invest in this new technology so that they could be the first to exploit it. It’s more important for the future of their business to keep on selling energy, not just gasoline or fossil diesel fuel.

So would I, Anthony. But here in Syracuse, my small garden gets too much shade from the all the Maple and Catawba trees.

But when I can homestead the desert SouthWest with photovoltaic self-assembling carbon nanocells, using seawater desalinated by the reverse osmosis supplied by graphene, then I’ll move out of the ‘cuse for the AZ.

This is going to be very important. At least the superstitious won’t find it creepy to fuel their diesels with oils from a genetically modified algae.

Biofuels and hydrogen power will be the one thing that ends terrorism. When we in the West no longer need petroleum from the Saudis, we can cut them loose. Once all of us “infidels” are far away from Mecca, they won’t have the need to become suicide bombers.